Light-transforming compositions.



I a citizen of the United States, and resident.

TED STATES; Para GE PETER; coorrm nnwrr'r, or nmewoon Manon, miw Jnnsnxg'nssieiron 'ro coornn.

HEWITT ELECTRIC COMPANY, OF NEW JERSEY.

HOIBOKEN, NEW JERSEY, A CORPORATION OF LIGHT-TRANSFORMING- COMPOSITIONS.

pecifieation of Letters Patent. 7 Pateimtedl June 27, 19116.. i

No Drawing. original application filed July 28, 1910, Serial-No. 578,557. Divided and this application filed October 20, 1913. Serial No. 796,171.

To all whom it may concern:

'Be it known that I, Pn'rniz Coornn Hnwrr'r,

of Ringwood Manor, county of Passaic, State of New Jersey, have invented certain new and useful Improvements in Light- Transforming Compositions, of which the following is a specification.

My invention relates to the class ,of de: vices employed for combining rays of a source of li ht which isdeficlent in some desired portion of the spectrum with rays of other wave length produced by the transformation of. certain rays or waves of one length into raysor wavesof another length and of such character as to supply the ray or wave length desired, within limits.

In a patent issued to me on December 22',

1908, hearing No. 907,598 and in a companion application Serial No. 453,187, filed by me September 15, 1908, I have described certain methods of producing and utilizing light rays of the character referred to, and my present invention relates more particularly to special compounds of materials to be used for transforming light rays and, when desired, adding light waves of definite character to light from any source.

Retentiveness of the fluorescent quality, or durability of the property'o'f transforim ing light, seems from experiment to be seriously modified by the internal structure or physical arrangement of the material in its final state: That is, the material retains this light transforming property better and for a longer period by reason of its being or having been in a state of internal-stress --or ture is fibrous in nature. 40

byreason of the fact that the internal strucalso that theconditiolis ofdryin or ,hardening of the material be proper ycarried out, as affecting the physical relation of the used with greater or less efiiciency and du rability or'retenti'veness, most excellent r e-- sultsare obtained by the use..0f rhodam 1n combined in proper proportions w1th acetate of cellulose 'towhich glycerin hasbeen added. A combination or association of the materials, having a structure retentive of the light transforming property under con- Itisimportant ditions of good efliciency and durability, can be secured in the foregoing manner.

A varnish is formed consisting of 70% of acetate of cellulose; 10% of glycerin and T 20 of acetic acid, the above percentages being the percentages by weight. To this is .added'technical acetone to make a 12% solution. 7

The acetate of cellulose, known in commerce as cellet may be used and prepared as in solution in alcohol or acetonefor convenience. The whole forms avarnish which when dry may beused either for reflecting purposes or as a light screen or filter, that is to say, it may be painted upon a suitable backing and when dry the transformed light reflected therefrom and mingled withthe light from the source, orit may be made into a film or painted upon a proper transparent backing and placed wholly or par-- tially around the source oflight so that more or less of the original light .and the transformed'light will be mingled.

In an a plication filed by me September 18, 1909 erial Number 518,325, I have described various forms of backings or supports-for varnishes of this general character and also materials which may be mixed with the varnish for the purpose of increas ing the light qualities thereof. When it is to be placed upon a backing or support to serve as a light reflector, I have'found it advantageous to use asthe immediate support for the .varnish a material, such for instance, as calcimine or white lead, or other material having the characteristics of dispersin light. In some instances it may be desire to mix the light-dispersing material with the varnish. I

-The proportions above given may be modified to a reasonable 'degree, but those given above are found to produce a material having efiiciency and durability combined.

- In-the drying of the material the aceticacidand acetone evaporate, leavlng the ace- "tate of cellulose, color (such as rhodamin), and an amount of glycerin as th light transformer.

The varnish may be painted upon a suitable temporary support and dried and then stripped off-from the support and used independently of any other support as the light reflector or screen.

Any desired number of coatings of the varnish may be painted upon the support in succession. I have found, for instance, that five coats quickly flowed, one after the other, gives a very eflicient result.

This application is a division of my -application Serial Number 573,557, filed July 23rd, 1910.

Iclaim as my invention: I 1. As a composition for -forming light transformers, acetate of cellulose, a fluores-' cent dye-stufi, glycerin, and suitable volatile solvents, substantially in the proportions described.

2. As a color fast varnish, acetate of cellulose, glycerin and a fluorescentcoloring material and suitable volatile solvents therefor, substantially in the proportions described.

"3. In a color fast varnish, acetic acid in which acetate of cellulose has been dissolved, in combination withglycerin substantially in the proportion described, and a coloring material in a volatile solvent.

Signed at New York in the county of New York and State of New York this 16th day of October A. D. 1913.

PETER COOPER HEWITT.

Witnessesz' WM. H. GAPEL,

Tnos. H. BROWN. 

